1. Field of the Invention
The present invention relates to trailers for hauling large, heavy loads. More particularly, but not by way of limitation, the present invention relates to a double gooseneck trailer which includes front and rear goosenecks pivotally connected to a front jeep and a rear dolly, respectively. Hydraulic cylinders automatically proportionateley shift weight from load unit axles to jeep axles for improved weight distribution. Steerable wheel assemblies, an articulated dolly, and a plurality of fifth wheel connections act in concert to achieve an improved turning radius.
2. Background
Trailers for hauling large, heavy loads are generally known in the prior art. Features have evolved to: improve the weight distribution of the load among the several axles, especially in relation to regulations which vary from state-to-state; improve the turning radius of the entire vehicle; facilitate loading and unloading; and improve off-road terrain clearance.
For example, U.S. Pat. No. 4,943,078 issued to McGhie et al. discloses a load unit disposed between a front carriage and a rear carriage, suspended thereto by front and rear goosenecks, respectively. A front carriage connects to a jeep which, in turn, connects to a tractor. The load is evenly distributed among the axles of the front and rear carriages by a hydraulic suspension system. At least some of the wheel units are articulated for steering to improve maneuverability. The apparatus described by the McGhie ""078 patent is intended for use on conventional roadways.
Further advances in a load hauling apparatus are disclosed in U.S. Pat. No. 5,112,073 issued to McGhie et al. The McGhie ""073 patent discloses a load supporting dolly including a steering system for attachment to a load or load unit. The McGhie ""073 patent does not provide controlled load sharing between the dolly and the carriages.
However, existing trailers for large, heavy loads still suffer from a number of limitations, particularly in regard to conforming to varying regulations along a route, accommodating off-road use, and maneuverability. All of these limitations are related to the general lack of configurability associated with prior art devices.
A limitation of prior art devices has been the inability to shift the relative load between axles on a load unit and axles on the front and rear jeeps, or carriages. This is of particular importance where weight may be credited differently to individual axles between jurisdictions. For example, a carriage may be configured with four-wheel axles while the load unit may be configured with multiple axles in a side-by-side configuration for eight wheel lines or even sixteen wheel lines. If a particular jurisdiction allows greater loads on an eight wheel line than on a four wheel line, it would be advantageous to allow distribution of the load to place a higher percentage of the load on the eight-wheel line. Also of concern is the number of axles in an axle group and the distance between such groups. These factors likewise play a role in the maximum weight transportable on a trailer in any given jurisdiction.
For the purposes of this application, the term xe2x80x9clinexe2x80x9d refers to a line across the trailer, perpendicular to the trailer""s longitudinal axis, along which wheels are located. Thus, a line could be a single four wheel axle or any number of side-by-side axles.
Another limitation of prior art devices is that, once loaded, the weight distribution is fixed among the various axles. At best, the weight could be evenly distributed across all of the axles or lines. In order to accommodate differing regulations, a trailer has to be loaded for compliance with the most restrictive jurisdiction. This task may be quite complex as a host of factors comes in to play, i.e., the number of wheels on each axle, the number of axles in a group of axles, the distance between particular axles, and the distribution of the load on the trailer. Regulations are typically the limiting factor in determining the maximum load for a given trailer. Thus, a trailer which is easily configured to adapt to varying regulations will likely be able to haul larger, heavier loads.
Yet another limitation of prior art devices is their limited application for off-road use. Even in light of steerable axles on the carriages and the use of a steerable dolly, the maneuverability of prior art devices is limited. As the overall length of the entire vehicle approaches 200 feet, maneuvering such a vehicle into place at a job site often presents a major hurdle. However, in off-road applications, the distribution of the weight is not controlled by regulation and thus, overall length of the vehicle and maneuverability may be of greater concern than weight loading on a particular axle.
It is thus an object of the present invention to provide a trailer for hauling large, heavy loads which may be readily configured to distribute weight between truck axles, carriage axles, and load unit axles, as desired.
It is a further object of the present invention to provide a trailer for hauling large, heavy loads in which the load weight may readily be redistributed between truck axles, carriage axles, and load unit axles as the load is hauled from jurisdiction-to-jurisdiction.
It is yet a further object of the present invention to provide a trailer for hauling large, heavy loads which is separately configurable for use on roadways or for off-road use. Such configuration may be changed without unloading the trailer.
It is still a further object of the present invention to provide a trailer for hauling large, heavy loads with an improved turning radius over prior art trailers for hauling comparable loads.
The present invention provides a trailer for hauling large, heavy loads which satisfies the needs and alleviates the problems mentioned above. The inventive trailer comprises a front jeep, a load unit, and an articulated rear dolly. A hydraulic suspension system and hydraulically actuated goosenecks allow precise, proportionate distribution of the load across groups of axles. Thus, the weight of the load may be proportionately distributed among various groups of axles to facilitate compliance with local regulations. In one embodiment, valves allow rapid changing of the ratio of the load carried by each gooseneck, relative to the load unit.
Steerable wheel assemblies on the load unit operate in conjunction with fifth wheel connections between the tractor and the front jeep, between the front jeep and the load unit, and between the load unit and the dolly and with an articulated joint in the dolly to provide an improved turning radius particularly for maneuvering on or near roadways.
For off-road use, the rear gooseneck may be removed along with the front jeep and rear dolly to improve maneuverability for off-road hauling. In this configuration, the overall length of the trailer is substantially shortened, thereby providing better maneuverability.
Finally, the goosenecks may also be removed for loading and unloading to provide better access to the load unit and the load.
Thus, an aspect of the present invention is the degree to which the trailer is configurable, allowing it to easily adapt to varying regulations from state-to-state. For example, axles may be grouped under the load unit in single axle groups, tandem groups, triple groups, quad groups, etc. The inventive gooseneck allows the load to be shifted between axle groups under the load unit and the fifth wheels such that the trailer may readily be configured for low axle loads under the loading surface and high fifth wheel loads, high axle loads and low fifth wheel loads, or any point in between.
Another example of the configurability of the present invention is the self steer feature of the axles under the load unit. The axle group may be configured to provide a selectable degree of steering, no steering, or even counter steering (turning the wheels opposite the direction of a turn) to achieve a desired level of maneuverability.
Further objects, features, and advantages of the present invention will be apparent to those skilled in the art upon examining the accompanying drawings and upon reading the following description of the preferred embodiments.